Here is a great quote that falls into the category of “you are what you eat”.
“What you pay attention to in the world is what you’re going to end up knowing”, from Happiness: Unlocking the Mysteries of Psycological Wealth, by Robert Biswas-Diener.
It’s okay to be under the influence of someone or a group. Let yourself be open to change and associate with people of like minded thinking and interests. It will be very good for you.
Wondering Around 
“The people we surround ourselves with either raise or lower our standards. They either help us to become the-best-version-of-ourselves or encourage us to become lesser versions of ourselves. We become like our friends. No man becomes great on his own. No woman becomes great on her own. The people around them help to make them great. We all need people in our lives who raise our standards, remind us of our essential purpose, and challenge us to become the-best-version-of-ourselves.”